The present invention relates to a dehydrating reagent which, in the production of frozen ground fish meat, enables the dehydration of fish meat after washing with water and besides improves the quality of frozen ground fish meat obtained.
Blanching and dehydration in the production of frozen ground fish meat are closely related and important steps. The objects of washing is to remove factors causing the denaturation of proteins during freezing and substances inhibiting the development of "ashi" (refers to stiffness with elasticity) essential to fish paste products as well as improve the appearance of "surimi" (referres to ground fish meat), so that insufficient washing cannot give "surimi" of high commercial value. On the other hand, sufficient washing swells fish meat because an extra water is contained in the fish meat, so that the fish meat in such state cannot be used as a material for "surimi". Dehydration becomes necessary to remove this extra water. In dehydration, the ease of dehydration, the so-called "squeezing", of fish meat has a great effect on the production efficiency of "surimi". Of factors having an effect on this ease of dehydration, the inner ones include freshness, fishing time, fishing ground, original water-retaining power of fish meat, etc., and the outer ones include mechanical operation, equipment, temperature and quality of water, etc. As described above, the ease of "squeezing" of fish meat is determined by various factors, and generally, the dehydration of fish meat is considered to be worst in winter. It seems that this is strongly due to the highness of the water holding capacity (WHC) of fish meat and the lowness of the water temperature, and those in this trade have a strong demand for improvement in the dehydration in this period of year.
The well-known method to improve the dehydration is to add sodium chloride, magnesium chloride or calcium chloride alone at the time of washing. This addition promotes the bonding of proteins with Na, Mg or Ca ions on washing, resulting in reduction in the charge of proteins and ease of dehydration. This swelling-inhibiting effect works best at an ionic strength of 0.05 to 0.1, but Na ions are fairly inferior in this effect to Mg or Ca ions. This seems to be due to difference in the bonding strength of these ions. As other effects of this addition, inhibition of protein elution is given. This protein elution-inhibiting effect is highest at an ionic strength of 0.04 to 0.06, and the amount of protein eluted increases as the ionic strength is far away from this range. From this information, it is considered to be desirable to add magnesium chloride or calcium chloride so that the ionic strength reaches about 0.05.
Addition of magnesium chloride or calcium chloride is surely effective in terms of improvement in the dehydration, but it largely affects meat quality to deteriorate the quality itself. Thus, this causes problems of lowering the quality of "surimi" itself obtained, for example the "ashi"-developing ability of fish paste products, as well as of promoting the denaturation of "surimi" on freezing due to the presence of Mg.sup.2+ or Ca.sup.2+ ions.